1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include <sys/mman.h>
struct map_data {
__u64 val[512 * 4];
};
struct bss_data {
__u64 in_val;
__u64 out_val;
};
static size_t roundup_page(size_t sz)
{
long page_size = sysconf(_SC_PAGE_SIZE);
return (sz + page_size - 1) / page_size * page_size;
}
void test_mmap(void)
{
const char *file = "test_mmap.o";
const char *probe_name = "raw_tracepoint/sys_enter";
const char *tp_name = "sys_enter";
const size_t bss_sz = roundup_page(sizeof(struct bss_data));
const size_t map_sz = roundup_page(sizeof(struct map_data));
const int zero = 0, one = 1, two = 2, far = 1500;
const long page_size = sysconf(_SC_PAGE_SIZE);
int err, duration = 0, i, data_map_fd;
struct bpf_program *prog;
struct bpf_object *obj;
struct bpf_link *link = NULL;
struct bpf_map *data_map, *bss_map;
void *bss_mmaped = NULL, *map_mmaped = NULL, *tmp1, *tmp2;
volatile struct bss_data *bss_data;
volatile struct map_data *map_data;
__u64 val = 0;
obj = bpf_object__open_file("test_mmap.o", NULL);
if (CHECK(IS_ERR(obj), "obj_open", "failed to open '%s': %ld\n",
file, PTR_ERR(obj)))
return;
prog = bpf_object__find_program_by_title(obj, probe_name);
if (CHECK(!prog, "find_probe", "prog '%s' not found\n", probe_name))
goto cleanup;
err = bpf_object__load(obj);
if (CHECK(err, "obj_load", "failed to load prog '%s': %d\n",
probe_name, err))
goto cleanup;
bss_map = bpf_object__find_map_by_name(obj, "test_mma.bss");
if (CHECK(!bss_map, "find_bss_map", ".bss map not found\n"))
goto cleanup;
data_map = bpf_object__find_map_by_name(obj, "data_map");
if (CHECK(!data_map, "find_data_map", "data_map map not found\n"))
goto cleanup;
data_map_fd = bpf_map__fd(data_map);
bss_mmaped = mmap(NULL, bss_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
bpf_map__fd(bss_map), 0);
if (CHECK(bss_mmaped == MAP_FAILED, "bss_mmap",
".bss mmap failed: %d\n", errno)) {
bss_mmaped = NULL;
goto cleanup;
}
/* map as R/W first */
map_mmaped = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
data_map_fd, 0);
if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
"data_map mmap failed: %d\n", errno)) {
map_mmaped = NULL;
goto cleanup;
}
bss_data = bss_mmaped;
map_data = map_mmaped;
CHECK_FAIL(bss_data->in_val);
CHECK_FAIL(bss_data->out_val);
CHECK_FAIL(map_data->val[0]);
CHECK_FAIL(map_data->val[1]);
CHECK_FAIL(map_data->val[2]);
CHECK_FAIL(map_data->val[far]);
link = bpf_program__attach_raw_tracepoint(prog, tp_name);
if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n", PTR_ERR(link)))
goto cleanup;
bss_data->in_val = 123;
val = 111;
CHECK_FAIL(bpf_map_update_elem(data_map_fd, &zero, &val, 0));
usleep(1);
CHECK_FAIL(bss_data->in_val != 123);
CHECK_FAIL(bss_data->out_val != 123);
CHECK_FAIL(map_data->val[0] != 111);
CHECK_FAIL(map_data->val[1] != 222);
CHECK_FAIL(map_data->val[2] != 123);
CHECK_FAIL(map_data->val[far] != 3 * 123);
CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &zero, &val));
CHECK_FAIL(val != 111);
CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &one, &val));
CHECK_FAIL(val != 222);
CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &two, &val));
CHECK_FAIL(val != 123);
CHECK_FAIL(bpf_map_lookup_elem(data_map_fd, &far, &val));
CHECK_FAIL(val != 3 * 123);
/* data_map freeze should fail due to R/W mmap() */
err = bpf_map_freeze(data_map_fd);
if (CHECK(!err || errno != EBUSY, "no_freeze",
"data_map freeze succeeded: err=%d, errno=%d\n", err, errno))
goto cleanup;
/* unmap R/W mapping */
err = munmap(map_mmaped, map_sz);
map_mmaped = NULL;
if (CHECK(err, "data_map_munmap", "data_map munmap failed: %d\n", errno))
goto cleanup;
/* re-map as R/O now */
map_mmaped = mmap(NULL, map_sz, PROT_READ, MAP_SHARED, data_map_fd, 0);
if (CHECK(map_mmaped == MAP_FAILED, "data_mmap",
"data_map R/O mmap failed: %d\n", errno)) {
map_mmaped = NULL;
goto cleanup;
}
map_data = map_mmaped;
/* map/unmap in a loop to test ref counting */
for (i = 0; i < 10; i++) {
int flags = i % 2 ? PROT_READ : PROT_WRITE;
void *p;
p = mmap(NULL, map_sz, flags, MAP_SHARED, data_map_fd, 0);
if (CHECK_FAIL(p == MAP_FAILED))
goto cleanup;
err = munmap(p, map_sz);
if (CHECK_FAIL(err))
goto cleanup;
}
/* data_map freeze should now succeed due to no R/W mapping */
err = bpf_map_freeze(data_map_fd);
if (CHECK(err, "freeze", "data_map freeze failed: err=%d, errno=%d\n",
err, errno))
goto cleanup;
/* mapping as R/W now should fail */
tmp1 = mmap(NULL, map_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
data_map_fd, 0);
if (CHECK(tmp1 != MAP_FAILED, "data_mmap", "mmap succeeded\n")) {
munmap(tmp1, map_sz);
goto cleanup;
}
bss_data->in_val = 321;
usleep(1);
CHECK_FAIL(bss_data->in_val != 321);
CHECK_FAIL(bss_data->out_val != 321);
CHECK_FAIL(map_data->val[0] != 111);
CHECK_FAIL(map_data->val[1] != 222);
CHECK_FAIL(map_data->val[2] != 321);
CHECK_FAIL(map_data->val[far] != 3 * 321);
/* check some more advanced mmap() manipulations */
/* map all but last page: pages 1-3 mapped */
tmp1 = mmap(NULL, 3 * page_size, PROT_READ, MAP_SHARED,
data_map_fd, 0);
if (CHECK(tmp1 == MAP_FAILED, "adv_mmap1", "errno %d\n", errno))
goto cleanup;
/* unmap second page: pages 1, 3 mapped */
err = munmap(tmp1 + page_size, page_size);
if (CHECK(err, "adv_mmap2", "errno %d\n", errno)) {
munmap(tmp1, map_sz);
goto cleanup;
}
/* map page 2 back */
tmp2 = mmap(tmp1 + page_size, page_size, PROT_READ,
MAP_SHARED | MAP_FIXED, data_map_fd, 0);
if (CHECK(tmp2 == MAP_FAILED, "adv_mmap3", "errno %d\n", errno)) {
munmap(tmp1, page_size);
munmap(tmp1 + 2*page_size, page_size);
goto cleanup;
}
CHECK(tmp1 + page_size != tmp2, "adv_mmap4",
"tmp1: %p, tmp2: %p\n", tmp1, tmp2);
/* re-map all 4 pages */
tmp2 = mmap(tmp1, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
data_map_fd, 0);
if (CHECK(tmp2 == MAP_FAILED, "adv_mmap5", "errno %d\n", errno)) {
munmap(tmp1, 3 * page_size); /* unmap page 1 */
goto cleanup;
}
CHECK(tmp1 != tmp2, "adv_mmap6", "tmp1: %p, tmp2: %p\n", tmp1, tmp2);
map_data = tmp2;
CHECK_FAIL(bss_data->in_val != 321);
CHECK_FAIL(bss_data->out_val != 321);
CHECK_FAIL(map_data->val
|